Change of Sign (CIE AS Maths: Pure 2)
Revision Note
Author
LucyExpertise
Head of STEM
Change of Sign
What does a change of sign mean?
- A sign change between f(a) to f(b) means there must be a root between a and b
- When an equation cannot be solved using the usual analytical methods, we can use change of sign to find approximate solutions
- We can say a root lies within a particular interval or is correct to a given accuracy
- Bounds can be used to show a root is correct
- Using sign change to find a root is only appropriate for continuous functions in a small interval
Exam Tip
- Remember this will only work if the function is continuous and the interval is small enough.
- Sign change questions may be part of bigger numerical methods questions.
Worked example
You've read 0 of your 0 free revision notes
Get unlimited access
to absolutely everything:
- Downloadable PDFs
- Unlimited Revision Notes
- Topic Questions
- Past Papers
- Model Answers
- Videos (Maths and Science)
Did this page help you?